1.\" $NetBSD: ccdconfig.8,v 1.4 1996/02/28 01:01:17 thorpej Exp $ 2.\" 3.\" Copyright (c) 1996 The NetBSD Foundation, Inc. 4.\" All rights reserved. 5.\" 6.\" This code is derived from software contributed to The NetBSD Foundation 7.\" by Jason R. Thorpe. 8.\" 9.\" Redistribution and use in source and binary forms, with or without 10.\" modification, are permitted provided that the following conditions 11.\" are met: 12.\" 1. Redistributions of source code must retain the above copyright 13.\" notice, this list of conditions and the following disclaimer. 14.\" 2. Redistributions in binary form must reproduce the above copyright 15.\" notice, this list of conditions and the following disclaimer in the 16.\" documentation and/or other materials provided with the distribution. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 19.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 20.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 21.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 22.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 23.\" BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 24.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 25.\" AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 26.\" OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28.\" SUCH DAMAGE. 29.\" 30.\" $FreeBSD$ 31.\" 32.Dd October 3, 2016 33.Dt CCDCONFIG 8 34.Os 35.Sh NAME 36.Nm ccdconfig 37.Nd configuration utility for the concatenated disk driver 38.Sh SYNOPSIS 39.Nm 40.Op Fl cv 41.Ar ccd 42.Ar ileave 43.Op Ar flags 44.Ar dev ... 45.Nm 46.Fl C 47.Op Fl v 48.Op Fl f Ar config_file 49.Nm 50.Fl u 51.Op Fl v 52.Ar ccd ... 53.Nm 54.Fl U 55.Op Fl v 56.Op Fl f Ar config_file 57.Nm 58.Fl g 59.Op Ar ccd ... 60.Sh DESCRIPTION 61The 62.Nm 63utility is used to dynamically configure and unconfigure concatenated disk 64devices, or ccds. 65For more information about the ccd, see 66.Xr ccd 4 . 67.Pp 68The options are as follows: 69.Bl -tag -width indent 70.It Fl c 71Configure a ccd. 72This is the default behavior of 73.Nm . 74.It Fl C 75Configure all ccd devices listed in the ccd configuration file. 76.It Fl f Ar config_file 77When configuring or unconfiguring all devices, read the file 78.Pa config_file 79instead of the default 80.Pa /etc/ccd.conf . 81.It Fl g 82Dump the current ccd configuration in a format suitable for use as the 83ccd configuration file. 84If no arguments are specified, every configured 85ccd is dumped. 86Otherwise, the configuration of each listed ccd is dumped. 87.It Fl u 88Unconfigure a ccd. 89.It Fl U 90Unconfigure all ccd devices listed the ccd configuration file. 91.It Fl v 92Cause 93.Nm 94to be verbose. 95.El 96.Pp 97A ccd is described on the command line and in the ccd configuration 98file by the name of the ccd, the interleave factor, the ccd configuration 99flags, and a list of one or more devices. 100The flags may be represented 101as a decimal number, a hexadecimal number, a comma-separated list 102of strings, or the word 103.Dq none . 104The flags are as follows: 105.Bd -literal -offset indent 106CCDF_UNIFORM 0x02 Use uniform interleave 107CCDF_MIRROR 0x04 Support mirroring 108CCDF_NO_OFFSET 0x08 Do not use an offset 109CCDF_LINUX 0x0A Linux md(4) compatibility 110.Ed 111.Pp 112The format in the 113configuration file appears exactly as if it were entered on the command line. 114Note that on the command line and in the configuration file, the 115.Pa flags 116argument is optional. 117.Bd -literal -offset indent 118# 119# /etc/ccd.conf 120# Configuration file for concatenated disk devices 121# 122 123# ccd ileave flags component devices 124ccd0 16 none /dev/da2s1 /dev/da3s1 125.Ed 126.Pp 127The component devices need to name partitions of type 128.Li FS_BSDFFS 129(or 130.Dq 4.2BSD 131as shown by 132.Xr disklabel 8 ) . 133.Pp 134If you want to use the 135.Tn Linux 136.Xr md 4 137compatibility mode, please be sure 138to read the notes in 139.Xr ccd 4 . 140.Sh FILES 141.Bl -tag -width /etc/ccd.conf -compact 142.It Pa /etc/ccd.conf 143default ccd configuration file 144.El 145.Sh EXAMPLES 146A number of 147.Nm 148examples are shown below. 149The arguments passed 150to 151.Nm 152are exactly the same as you might place in the 153.Pa /etc/ccd.conf 154configuration file. 155The first example creates a 4-disk stripe out of 156four scsi disk partitions. 157The stripe uses a 64 sector interleave. 158The second example is an example of a complex stripe/mirror combination. 159It reads as a two disk stripe of da4 and da5 which is mirrored 160to a two disk stripe of da6 and da7. 161The last example is a simple 162mirror. 163The second slice of /dev/da8 is mirrored with the third slice of /dev/da9 164and assigned to ccd0. 165.Bd -literal 166# ccdconfig ccd0 64 none /dev/da0s1 /dev/da1s1 /dev/da2s1 /dev/da3s1 167# ccdconfig ccd0 128 CCDF_MIRROR /dev/da4 /dev/da5 /dev/da6 /dev/da7 168# ccdconfig ccd0 128 CCDF_MIRROR /dev/da8s2 /dev/da9s3 169.Ed 170.Pp 171The following are matching commands in 172.Tn Linux 173and 174.Fx 175to create a RAID-0 in 176.Tn Linux 177and read it from 178.Fx . 179.Bd -literal 180# Create a RAID-0 on Linux: 181mdadm --create --chunk=32 --level=0 --raid-devices=2 /dev/md0 \\ 182 /dev/hda1 /dev/hdb1 183# Make the RAID-0 just created available on FreeBSD: 184ccdconfig -c /dev/ccd0 32 linux /dev/ada0s1 /dev/ada0s2 185.Ed 186.Pp 187When you create a new ccd disk you generally want to 188.Xr fdisk 8 189and 190.Xr disklabel 8 191it before doing anything else. 192Once you create the initial label you can 193edit it, adding additional partitions. 194The label itself takes up the first 19516 sectors of the ccd disk. 196If all you are doing is creating file systems 197with newfs, you do not have to worry about this as newfs will skip the 198label area. 199However, if you intend to 200.Xr dd 1 201to or from a ccd partition it is usually a good idea to construct the 202partition such that it does not overlap the label area. 203For example, if 204you have A ccd disk with 10000 sectors you might create a 'd' partition 205with offset 16 and size 9984. 206.Bd -literal 207# disklabel ccd0 > /tmp/disklabel.ccd0 208# disklabel -Rr ccd0 /tmp/disklabel.ccd0 209# disklabel -e ccd0 210.Ed 211.Pp 212The disklabeling of a ccd disk is usually a one-time affair. 213If you reboot the machine and reconfigure the ccd disk, 214the disklabel you 215had created before will still be there and not require reinitialization. 216Beware that changing any ccd parameters: interleave, flags, or the 217device list making up the ccd disk, will usually destroy any prior 218data on that ccd disk. 219If this occurs it is usually a good idea to 220reinitialize the label before [re]constructing your ccd disk. 221.Sh RECOVERY 222An error on a ccd disk is usually unrecoverable unless you are using the 223mirroring option. 224But mirroring has its own perils: It assumes that 225both copies of the data at any given sector are the same. 226This holds true 227until a write error occurs or until you replace either side of the mirror. 228This is a poor-man's mirroring implementation. 229It works well enough that if 230you begin to get disk errors you should be able to backup the ccd disk, 231replace the broken hardware, and then regenerate the ccd disk. 232If you need 233more than this you should look into external hardware RAID SCSI boxes, 234RAID controllers (see GENERIC), 235or software RAID systems such as 236.Xr geom 8 237and 238.Xr gvinum 8 . 239.Sh SEE ALSO 240.Xr dd 1 , 241.Xr ccd 4 , 242.Xr disklabel 8 , 243.Xr fdisk 8 , 244.Xr gvinum 8 , 245.Xr rc 8 246.Sh HISTORY 247The 248.Nm 249utility first appeared in 250.Nx 1.1 . 251.Sh BUGS 252The initial disklabel returned by 253.Xr ccd 4 254specifies only 3 partitions. 255One needs to change the number of partitions to 8 using 256.Dq Nm disklabel Fl e 257to get the usual 258.Bx 259expectations. 260